* Re: [WIP/PATCH] restart writes on EINTR
2022-06-10 19:05 ` Måns Rullgård
@ 2022-06-11 2:17 ` Eric Wong
0 siblings, 0 replies; 3+ messages in thread
From: Eric Wong @ 2022-06-11 2:17 UTC (permalink / raw)
To: Måns Rullgård; +Cc: sox-devel
Måns Rullgård <mans@mansr.com> wrote:
> The return value and ft->tell_off will be wrong in case the fwrite() was
> restarted.
Right, updated patch (covers fread + fflush) below; but still
somewhere else is hitting EINTR... I'm still alive for now,
but not feeling great about it :<
> What did you do that caused the EINTR error?
SIGWINCH
-------8<-------
Subject: [PATCH] WIP EINTR handling
Still incomplete, SIGWINCH in a complex pipeline
(sox -M "|sox ..." "|sox ..." -p) is still causing problems for me
even with this patch. Not sure how much time I can devote to
tracking more of it down of if I'll just setsid the parent script
and call it a day since I fear this can turn into a long-term
whack-a-mole situation...
---
src/formats.c | 6 ++++-
src/formats_i.c | 59 +++++++++++++++++++++++++++++++++++++++----------
2 files changed, 52 insertions(+), 13 deletions(-)
diff --git a/src/formats.c b/src/formats.c
index 3fcf4382..31ab99f8 100644
--- a/src/formats.c
+++ b/src/formats.c
@@ -370,6 +370,10 @@ static sox_bool is_url(char const * text) /* detects only wget-supported URLs */
static int xfclose(FILE * file, lsx_io_type io_type)
{
+ int ret;
+ do {
+ ret = fflush(file);
+ } while (ret == EOF && errno == EINTR);
return
#ifdef HAVE_POPEN
io_type != lsx_io_file? pclose(file) :
@@ -1064,7 +1068,7 @@ int sox_close(sox_format_t * ft)
if (ft->fp == stdin) {
sox_globals.stdin_in_use_by = NULL;
} else if (ft->fp == stdout) {
- fflush(stdout);
+ lsx_flush(ft);
sox_globals.stdout_in_use_by = NULL;
} else if (ft->fp) {
xfclose(ft->fp, ft->io_type);
diff --git a/src/formats_i.c b/src/formats_i.c
index 7048040d..c4ead348 100644
--- a/src/formats_i.c
+++ b/src/formats_i.c
@@ -95,11 +95,24 @@ int lsx_check_read_params(sox_format_t * ft, unsigned channels,
*/
size_t lsx_readbuf(sox_format_t * ft, void *buf, size_t len)
{
- size_t ret = fread(buf, (size_t) 1, len, (FILE*)ft->fp);
- if (ret != len && ferror((FILE*)ft->fp))
- lsx_fail_errno(ft, errno, "lsx_readbuf");
- ft->tell_off += ret;
- return ret;
+ FILE *fp = (FILE*)ft->fp;
+
+ while (1) {
+ size_t ret = fread(buf, 1, len, fp);
+ ft->tell_off += ret;
+
+ if (ret)
+ return ret;
+
+ if (feof(fp))
+ break;
+ if (ferror(fp) && errno != EINTR) {
+ lsx_fail_errno(ft, errno, "lsx_readbuf");
+ break;
+ }
+ }
+
+ return 0;
}
/* Skip input without seeking. */
@@ -129,13 +142,29 @@ int lsx_padbytes(sox_format_t * ft, size_t n)
*/
size_t lsx_writebuf(sox_format_t * ft, void const * buf, size_t len)
{
- size_t ret = fwrite(buf, (size_t) 1, len, (FILE*)ft->fp);
- if (ret != len) {
- lsx_fail_errno(ft, errno, "error writing output file");
- clearerr((FILE*)ft->fp); /* Allows us to seek back to write header */
+ FILE *fp = (FILE*)ft->fp;
+ const char *c = (const char *)buf;
+ sox_uint64_t orig_off = ft->tell_off;
+
+ while (len) {
+ size_t ret = fwrite(c, 1, len, fp);
+
+ ft->tell_off += ret;
+ c += ret;
+ len -= ret;
+ if (len && ferror(fp)) {
+ if (errno == EINTR) {
+ clearerr(fp);
+ /* retry */
+ } else {
+ lsx_fail_errno(ft, errno, "error writing output file");
+ clearerr(fp); /* Allows us to seek back to write header */
+ break;
+ }
+ }
}
- ft->tell_off += ret;
- return ret;
+
+ return ft->tell_off - orig_off;
}
sox_uint64_t lsx_filelength(sox_format_t * ft)
@@ -148,7 +177,13 @@ sox_uint64_t lsx_filelength(sox_format_t * ft)
int lsx_flush(sox_format_t * ft)
{
- return fflush((FILE*)ft->fp);
+ int ret;
+
+ do {
+ ret = fflush((FILE *)ft->fp);
+ } while (ret == EOF && errno == EINTR);
+
+ return ret;
}
off_t lsx_tell(sox_format_t * ft)
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